A facile approach for surface modification of TiO₂ nanosheets to enhance photocatalytic hydrogen evolution activity

TiO₂ nanosheets have a great potential in photocatalytic H₂ evolution, but they suffer from low catalytic activity at present. Although the surface modification has been extensively used to improve the catalytic performance, regulating the surface functional groups of TiO₂ nanosheets to enhance the photocatalytic activity has been largely overlooked. In this study, we attempt to tailor the surface properties of TiO₂ nanosheets by adjusting the surface functional groups so as to improve their photocatalytic H₂ production activity. With adding a small amount of alcohols in the synthesis system, the surface hydroxyl groups of TiO₂ nanosheets were regulated successfully. Interestingly, the TiO₂ nanosheets prepared with adding ethylene glycol possess the significantly more surface hydroxyl groups and exhibit a narrower bandgap, a higher hydrophilicity, and a slower recombination rate of photo-induced carriers than the conventional nanosheets. Benefit from these special properties, the ability of the hydroxyl-rich TiO₂ nanosheets to photocatalyze H₂ evolution is obviously improved.